This is also very interesting (From Wikipedia):
In the audiophile community, the sound from the SACD format is thought to be significantly better compared to older format Red Book CD recordings.[35] However, In September 2007, the Audio Engineering Society published the results of a year-long trial in which a range of subjects including professional recording engineers were asked to discern the difference between SACD and compact disc audio (44.1 kHz/16 bit) under double blind test conditions. Out of 554 trials, there were 276 correct answers, a 49.8% success rate corresponding almost exactly to the 50% that would have been expected by chance guessing alone.[36] The authors suggested that different mixes for the two formats might be causing perceived differences, and commented:
"Now, it is very difficult to use negative results to prove the inaudibility of any given phenomenon or process. There is always the remote possibility that a different system or more finely attuned pair of ears would reveal a difference. But we have gathered enough data, using sufficiently varied and capable systems and listeners, to state that the burden of proof has now shifted. Further claims that careful 16/44.1 encoding audibly degrades high resolution signals must be supported by properly controlled double-blind tests.[37][38]
This conclusion is contentious among a large segment of audio engineers who work with high resolution material and many within the audiophile community.[39] Some have questioned the basic methodology and the equipment used in the AES study.[40] "
